The present invention pertains to urethane oligomer modified epoxy resin compositions and cured products therefrom.
R. E. Hefner, Jr. and V. B. Messick disclose in copending U.S. patent application Ser. No. 734,516, now U.S. Pat. No. 4,618,658 filed May 16, 1985 polymer modified epoxy resin compositions and vinyl ester resin compositions wherein said epoxy resin compositions are prepared by (A) reacting a portion of the epoxy groups of an epoxy resin with a compound containing a group reactive with an epoxide group and a polymerizable ethylenically unsaturated group; (B) copolymerizing the resultant product with at least one vinyl terminated urethane oligomer optionally with at least one polymerizable ethylenically unsaturated monomer. These polymer modified vinyl ester resins are produced by reaction of the aforesaid polymer modified epoxy resin and a monounsaturated monocarboxylic acid.
J. A. Clarke in U.S. Pat. Nos. 3,676,397 issued July 11, 1972, 3,687,897 issued Aug. 29, 1972, 3,767,624 issued Oct. 23, 1973, 3,789,053 issued Jan. 29, 1974 and 3,876,618 issued Apr. 8, 1975 disclose the preparation of oxazolidinone modified epoxy resins. These modified epoxy resin compositions are prepared by reacting an epoxy resin with a polyisocyanate in the presence of a suitable catalyst for oxazolidinone formation.
The present invention provides novel urethane oligomer modified epoxy resin compositions produced by reacting an epoxy resin and a urethane oligomer containing at least one oxyalkylene group and both polymerizable ethylenic unsaturation and isocyanate (isothiocyanate) groups in the presence of a suitable catalyst for oxazolidinone (thiazolidinone) formation.
The modified epoxy resin compositions of the present invention can be cured with conventional curing agents. They can also be employed to prepare urethane modified vinyl ester resins by reaction with polymerizable ethylenically unsaturated monocarboxylic acids or half esters of polymerizable ethylenically unsaturated dicarboxylic acids or combinations thereof.